As you know you can send emails via the CURL functions in MBS Plugins for Xojo and FileMaker. To have your mails how up in sent folder, you need to upload them to the IMAP server. The following script does it for FileMaker. Key thing is to pass in URL to IMAP Server with name of Mailbox, e.g. "imap://imap.monkeybreadsoftware.de/INBOX.Sent". Than you set the upload option and provide the data to send. Of course you should use SSL, certificate verification and pass in your credentials. So here the FileMaker script from the sample database: